diff --git a/doc/api/repl.md b/doc/api/repl.md
index be3c0b8c52e2ab..7c7ce9b3a303f5 100644
--- a/doc/api/repl.md
+++ b/doc/api/repl.md
@@ -575,8 +575,9 @@ changes:
   * `breakEvalOnSigint` {boolean} Stop evaluating the current piece of code when
     `SIGINT` is received, such as when `Ctrl+C` is pressed. This cannot be used
     together with a custom `eval` function. **Default:** `false`.
-  * `preview` {boolean} Defines if the repl prints output previews or not.
-     **Default:** `true`. Always `false` in case `terminal` is falsy.
+  * `preview` {boolean} Defines if the repl prints autocomplete and output
+    previews or not. **Default:** `true`. If `terminal` is falsy, then there are
+    no previews and the value of `preview` has no effect.
 * Returns: {repl.REPLServer}
 
 The `repl.start()` method creates and starts a [`repl.REPLServer`][] instance.
diff --git a/lib/internal/repl/utils.js b/lib/internal/repl/utils.js
index c4280c1d1fe9e2..bdc402ee08715d 100644
--- a/lib/internal/repl/utils.js
+++ b/lib/internal/repl/utils.js
@@ -28,6 +28,10 @@ const {
   moveCursor,
 } = require('readline');
 
+const {
+  commonPrefix
+} = require('internal/readline/utils');
+
 const { inspect } = require('util');
 
 const debug = require('internal/util/debuglog').debuglog('repl');
@@ -119,24 +123,103 @@ function isRecoverableError(e, code) {
 function setupPreview(repl, contextSymbol, bufferSymbol, active) {
   // Simple terminals can't handle previews.
   if (process.env.TERM === 'dumb' || !active) {
-    return { showInputPreview() {}, clearPreview() {} };
+    return { showPreview() {}, clearPreview() {} };
   }
 
-  let preview = null;
-  let lastPreview = '';
+  let inputPreview = null;
+  let lastInputPreview = '';
+
+  let previewCompletionCounter = 0;
+  let completionPreview = null;
 
   const clearPreview = () => {
-    if (preview !== null) {
+    if (inputPreview !== null) {
       moveCursor(repl.output, 0, 1);
       clearLine(repl.output);
       moveCursor(repl.output, 0, -1);
-      lastPreview = preview;
-      preview = null;
+      lastInputPreview = inputPreview;
+      inputPreview = null;
+    }
+    if (completionPreview !== null) {
+      // Prevent cursor moves if not necessary!
+      const move = repl.line.length !== repl.cursor;
+      if (move) {
+        cursorTo(repl.output, repl._prompt.length + repl.line.length);
+      }
+      clearLine(repl.output, 1);
+      if (move) {
+        cursorTo(repl.output, repl._prompt.length + repl.cursor);
+      }
+      completionPreview = null;
     }
   };
 
+  function showCompletionPreview(line, insertPreview) {
+    previewCompletionCounter++;
+
+    const count = previewCompletionCounter;
+
+    repl.completer(line, (error, data) => {
+      // Tab completion might be async and the result might already be outdated.
+      if (count !== previewCompletionCounter) {
+        return;
+      }
+
+      if (error) {
+        debug('Error while generating completion preview', error);
+        return;
+      }
+
+      // Result and the text that was completed.
+      const [rawCompletions, completeOn] = data;
+
+      if (!rawCompletions || rawCompletions.length === 0) {
+        return;
+      }
+
+      // If there is a common prefix to all matches, then apply that portion.
+      const completions = rawCompletions.filter((e) => e);
+      const prefix = commonPrefix(completions);
+
+      // No common prefix found.
+      if (prefix.length <= completeOn.length) {
+        return;
+      }
+
+      const suffix = prefix.slice(completeOn.length);
+
+      const totalLength = repl.line.length +
+                          repl._prompt.length +
+                          suffix.length +
+                          (repl.useColors ? 0 : 4);
+
+      // TODO(BridgeAR): Fix me. This should not be necessary. See similar
+      // comment in `showPreview()`.
+      if (totalLength > repl.columns) {
+        return;
+      }
+
+      if (insertPreview) {
+        repl._insertString(suffix);
+        return;
+      }
+
+      completionPreview = suffix;
+
+      const result = repl.useColors ?
+        `\u001b[90m${suffix}\u001b[39m` :
+        ` // ${suffix}`;
+
+      if (repl.line.length !== repl.cursor) {
+        cursorTo(repl.output, repl._prompt.length + repl.line.length);
+      }
+      repl.output.write(result);
+      cursorTo(repl.output, repl._prompt.length + repl.cursor);
+    });
+  }
+
   // This returns a code preview for arbitrary input code.
-  function getPreviewInput(input, callback) {
+  function getInputPreview(input, callback) {
     // For similar reasons as `defaultEval`, wrap expressions starting with a
     // curly brace with parenthesis.
     if (input.startsWith('{') && !input.endsWith(';')) {
@@ -184,23 +267,41 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
     }, () => callback(new ERR_INSPECTOR_NOT_AVAILABLE()));
   }
 
-  const showInputPreview = () => {
+  const showPreview = () => {
     // Prevent duplicated previews after a refresh.
-    if (preview !== null) {
+    if (inputPreview !== null) {
       return;
     }
 
     const line = repl.line.trim();
 
-    // Do not preview if the command is buffered or if the line is empty.
-    if (repl[bufferSymbol] || line === '') {
+    // Do not preview in case the line only contains whitespace.
+    if (line === '') {
+      return;
+    }
+
+    // Add the autocompletion preview.
+    // TODO(BridgeAR): Trigger the input preview after the completion preview.
+    // That way it's possible to trigger the input prefix including the
+    // potential completion suffix. To do so, we also have to change the
+    // behavior of `enter` and `escape`:
+    // Enter should automatically add the suffix to the current line as long as
+    // escape was not pressed. We might even remove the preview in case any
+    // cursor movement is triggered.
+    if (typeof repl.completer === 'function') {
+      const insertPreview = false;
+      showCompletionPreview(repl.line, insertPreview);
+    }
+
+    // Do not preview if the command is buffered.
+    if (repl[bufferSymbol]) {
       return;
     }
 
-    getPreviewInput(line, (error, inspected) => {
+    getInputPreview(line, (error, inspected) => {
       // Ignore the output if the value is identical to the current line and the
       // former preview is not identical to this preview.
-      if ((line === inspected && lastPreview !== inspected) ||
+      if ((line === inspected && lastInputPreview !== inspected) ||
           inspected === null) {
         return;
       }
@@ -215,7 +316,7 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
         return;
       }
 
-      preview = inspected;
+      inputPreview = inspected;
 
       // Limit the output to maximum 250 characters. Otherwise it becomes a)
       // difficult to read and b) non terminal REPLs would visualize the whole
@@ -235,21 +336,50 @@ function setupPreview(repl, contextSymbol, bufferSymbol, active) {
 
       repl.output.write(`\n${result}`);
       moveCursor(repl.output, 0, -1);
-      cursorTo(repl.output, repl.cursor + repl._prompt.length);
+      cursorTo(repl.output, repl._prompt.length + repl.cursor);
     });
   };
 
+  // -------------------------------------------------------------------------//
+  // Replace multiple interface functions. This is required to fully support  //
+  // previews without changing readlines behavior.                            //
+  // -------------------------------------------------------------------------//
+
   // Refresh prints the whole screen again and the preview will be removed
   // during that procedure. Print the preview again. This also makes sure
   // the preview is always correct after resizing the terminal window.
-  const tmpRefresh = repl._refreshLine.bind(repl);
+  const originalRefresh = repl._refreshLine.bind(repl);
   repl._refreshLine = () => {
-    preview = null;
-    tmpRefresh();
-    showInputPreview();
+    inputPreview = null;
+    originalRefresh();
+    showPreview();
+  };
+
+  let insertCompletionPreview = true;
+  // Insert the longest common suffix of the current input in case the user
+  // moves to the right while already being at the current input end.
+  const originalMoveCursor = repl._moveCursor.bind(repl);
+  repl._moveCursor = (dx) => {
+    const currentCursor = repl.cursor;
+    originalMoveCursor(dx);
+    if (currentCursor + dx > repl.line.length &&
+        typeof repl.completer === 'function' &&
+        insertCompletionPreview) {
+      const insertPreview = true;
+      showCompletionPreview(repl.line, insertPreview);
+    }
+  };
+
+  // This is the only function that interferes with the completion insertion.
+  // Monkey patch it to prevent inserting the completion when it shouldn't be.
+  const originalClearLine = repl.clearLine.bind(repl);
+  repl.clearLine = () => {
+    insertCompletionPreview = false;
+    originalClearLine();
+    insertCompletionPreview = true;
   };
 
-  return { showInputPreview, clearPreview };
+  return { showPreview, clearPreview };
 }
 
 module.exports = {
diff --git a/lib/readline.js b/lib/readline.js
index bd70754b5b48a2..7607d7fb03c440 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -602,8 +602,11 @@ function charLengthLeft(str, i) {
 }
 
 function charLengthAt(str, i) {
-  if (str.length <= i)
-    return 0;
+  if (str.length <= i) {
+    // Pretend to move to the right. This is necessary to autocomplete while
+    // moving to the right.
+    return 1;
+  }
   return str.codePointAt(i) >= kUTF16SurrogateThreshold ? 2 : 1;
 }
 
@@ -958,6 +961,7 @@ Interface.prototype._ttyWrite = function(s, key) {
         }
         break;
 
+      // TODO(BridgeAR): This seems broken?
       case 'w': // Delete backwards to a word boundary
       case 'backspace':
         this._deleteWordLeft();
diff --git a/lib/repl.js b/lib/repl.js
index 9d28234900f215..d721f1e6890603 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -821,7 +821,7 @@ function REPLServer(prompt,
 
   const {
     clearPreview,
-    showInputPreview
+    showPreview
   } = setupPreview(
     this,
     kContextId,
@@ -832,7 +832,6 @@ function REPLServer(prompt,
   // Wrap readline tty to enable editor mode and pausing.
   const ttyWrite = self._ttyWrite.bind(self);
   self._ttyWrite = (d, key) => {
-    clearPreview();
     key = key || {};
     if (paused && !(self.breakEvalOnSigint && key.ctrl && key.name === 'c')) {
       pausedBuffer.push(['key', [d, key]]);
@@ -844,14 +843,17 @@ function REPLServer(prompt,
           self.cursor === 0 && self.line.length === 0) {
         self.clearLine();
       }
+      clearPreview();
       ttyWrite(d, key);
-      showInputPreview();
+      showPreview();
       return;
     }
 
     // Editor mode
     if (key.ctrl && !key.shift) {
       switch (key.name) {
+        // TODO(BridgeAR): There should not be a special mode necessary for full
+        // multiline support.
         case 'd': // End editor mode
           _turnOffEditorMode(self);
           sawCtrlD = true;
diff --git a/test/parallel/test-repl-editor.js b/test/parallel/test-repl-editor.js
index 969f6172b3fb70..b340bd66313971 100644
--- a/test/parallel/test-repl-editor.js
+++ b/test/parallel/test-repl-editor.js
@@ -5,10 +5,11 @@ const assert = require('assert');
 const repl = require('repl');
 const ArrayStream = require('../common/arraystream');
 
-// \u001b[1G - Moves the cursor to 1st column
+// \u001b[nG - Moves the cursor to n st column
 // \u001b[0J - Clear screen
-// \u001b[3G - Moves the cursor to 3rd column
+// \u001b[0K - Clear to line end
 const terminalCode = '\u001b[1G\u001b[0J> \u001b[3G';
+const previewCode = (str, n) => ` // ${str}\x1B[${n}G\x1B[0K`;
 const terminalCodeRegex = new RegExp(terminalCode.replace(/\[/g, '\\['), 'g');
 
 function run({ input, output, event, checkTerminalCodes = true }) {
@@ -17,7 +18,9 @@ function run({ input, output, event, checkTerminalCodes = true }) {
 
   stream.write = (msg) => found += msg.replace('\r', '');
 
-  let expected = `${terminalCode}.editor\n` +
+  let expected = `${terminalCode}.ed${previewCode('itor', 6)}i` +
+                   `${previewCode('tor', 7)}t${previewCode('or', 8)}o` +
+                   `${previewCode('r', 9)}r\n` +
                  '// Entering editor mode (^D to finish, ^C to cancel)\n' +
                  `${input}${output}\n${terminalCode}`;
 
diff --git a/test/parallel/test-repl-multiline.js b/test/parallel/test-repl-multiline.js
index 6498923b62ecfc..f99b91c84b0a85 100644
--- a/test/parallel/test-repl-multiline.js
+++ b/test/parallel/test-repl-multiline.js
@@ -23,14 +23,23 @@ function run({ useColors }) {
   r.on('exit', common.mustCall(() => {
     const actual = output.split('\n');
 
+    const firstLine = useColors ?
+      '\x1B[1G\x1B[0J \x1B[1Gco\x1B[90mn\x1B[39m\x1B[3G\x1B[0Knst ' +
+        'fo\x1B[90mr\x1B[39m\x1B[9G\x1B[0Ko = {' :
+      '\x1B[1G\x1B[0J \x1B[1Gco // n\x1B[3G\x1B[0Knst ' +
+        'fo // r\x1B[9G\x1B[0Ko = {';
+
     // Validate the output, which contains terminal escape codes.
     assert.strictEqual(actual.length, 6 + process.features.inspector);
-    assert.ok(actual[0].endsWith(input[0]));
+    assert.strictEqual(actual[0], firstLine);
     assert.ok(actual[1].includes('... '));
     assert.ok(actual[1].endsWith(input[1]));
     assert.ok(actual[2].includes('undefined'));
-    assert.ok(actual[3].endsWith(input[2]));
     if (process.features.inspector) {
+      assert.ok(
+        actual[3].endsWith(input[2]),
+        `"${actual[3]}" should end with "${input[2]}"`
+      );
       assert.ok(actual[4].includes(actual[5]));
       assert.strictEqual(actual[4].includes('//'), !useColors);
     }
diff --git a/test/parallel/test-repl-preview.js b/test/parallel/test-repl-preview.js
index 92e73dd245056f..65b56904cb03b9 100644
--- a/test/parallel/test-repl-preview.js
+++ b/test/parallel/test-repl-preview.js
@@ -72,13 +72,13 @@ async function tests(options) {
      '\x1B[36m[Function: foo]\x1B[39m',
      '\x1B[1G\x1B[0Jrepl > \x1B[8G'],
     ['koo', [2, 4], '[Function: koo]',
-     'koo',
+     'k\x1B[90moo\x1B[39m\x1B[9G\x1B[0Ko\x1B[90mo\x1B[39m\x1B[10G\x1B[0Ko',
      '\x1B[90m[Function: koo]\x1B[39m\x1B[1A\x1B[11G\x1B[1B\x1B[2K\x1B[1A\r',
      '\x1B[36m[Function: koo]\x1B[39m',
      '\x1B[1G\x1B[0Jrepl > \x1B[8G'],
     ['a', [1, 2], undefined],
     ['{ a: true }', [2, 3], '{ a: \x1B[33mtrue\x1B[39m }',
-     '{ a: true }\r',
+     '{ a: tru\x1B[90me\x1B[39m\x1B[16G\x1B[0Ke }\r',
      '{ a: \x1B[33mtrue\x1B[39m }',
      '\x1B[1G\x1B[0Jrepl > \x1B[8G'],
     ['1n + 2n', [2, 5], '\x1B[33m3n\x1B[39m',
@@ -88,12 +88,12 @@ async function tests(options) {
      '\x1B[33m3n\x1B[39m',
      '\x1B[1G\x1B[0Jrepl > \x1B[8G'],
     ['{ a: true };', [2, 4], '\x1B[33mtrue\x1B[39m',
-     '{ a: true };',
+     '{ a: tru\x1B[90me\x1B[39m\x1B[16G\x1B[0Ke };',
      '\x1B[90mtrue\x1B[39m\x1B[1A\x1B[20G\x1B[1B\x1B[2K\x1B[1A\r',
      '\x1B[33mtrue\x1B[39m',
      '\x1B[1G\x1B[0Jrepl > \x1B[8G'],
     [' \t { a: true};', [2, 5], '\x1B[33mtrue\x1B[39m',
-     ' \t { a: true}',
+     ' \t { a: tru\x1B[90me\x1B[39m\x1B[19G\x1B[0Ke}',
      '\x1B[90m{ a: true }\x1B[39m\x1B[1A\x1B[21G\x1B[1B\x1B[2K\x1B[1A;',
      '\x1B[90mtrue\x1B[39m\x1B[1A\x1B[22G\x1B[1B\x1B[2K\x1B[1A\r',
      '\x1B[33mtrue\x1B[39m',
diff --git a/test/parallel/test-repl-top-level-await.js b/test/parallel/test-repl-top-level-await.js
index cecbd3ab4563d0..47fcb8530dee77 100644
--- a/test/parallel/test-repl-top-level-await.js
+++ b/test/parallel/test-repl-top-level-await.js
@@ -60,7 +60,7 @@ const testMe = repl.start({
   prompt: PROMPT,
   stream: putIn,
   terminal: true,
-  useColors: false,
+  useColors: true,
   breakEvalOnSigint: true
 });
 
@@ -84,69 +84,99 @@ async function ordinaryTests() {
     'function koo() { return Promise.resolve(4); }'
   ]);
   const testCases = [
-    [ 'await Promise.resolve(0)', '0' ],
-    [ '{ a: await Promise.resolve(1) }', '{ a: 1 }' ],
-    [ '_', '// { a: 1 }\r', { line: 0 } ],
+    [ 'await Promise.resolve(0)',
+      // Auto completion preview with colors stripped.
+      ['awaitaititt Proroomiseisesee.resolveolvelvevee(0)\r', '0']
+    ],
+    [ '{ a: await Promise.resolve(1) }',
+      // Auto completion preview with colors stripped.
+      ['{ a: awaitaititt Proroomiseisesee.resolveolvelvevee(1) }\r',
+       '{ a: 1 }']
+    ],
+    [ '_', '{ a: 1 }\r', { line: 0 } ],
     [ 'let { aa, bb } = await Promise.resolve({ aa: 1, bb: 2 }), f = 5;',
-      'undefined' ],
-    [ 'aa', ['// 1\r', '1'] ],
-    [ 'bb', ['// 2\r', '2'] ],
-    [ 'f', ['// 5\r', '5'] ],
-    [ 'let cc = await Promise.resolve(2)', 'undefined' ],
-    [ 'cc', ['// 2\r', '2'] ],
-    [ 'let dd;', 'undefined' ],
-    [ 'dd', 'undefined' ],
-    [ 'let [ii, { abc: { kk } }] = [0, { abc: { kk: 1 } }];', 'undefined' ],
-    [ 'ii', ['// 0\r', '0'] ],
-    [ 'kk', ['// 1\r', '1'] ],
-    [ 'var ll = await Promise.resolve(2);', 'undefined' ],
-    [ 'll', ['// 2\r', '2'] ],
+      [
+        'letett { aa, bb } = awaitaititt Proroomiseisesee.resolveolvelvevee' +
+          '({ aa: 1, bb: 2 }), f = 5;\r'
+      ]
+    ],
+    [ 'aa', ['1\r', '1'] ],
+    [ 'bb', ['2\r', '2'] ],
+    [ 'f', ['5\r', '5'] ],
+    [ 'let cc = await Promise.resolve(2)',
+      ['letett cc = awaitaititt Proroomiseisesee.resolveolvelvevee(2)\r']
+    ],
+    [ 'cc', ['2\r', '2'] ],
+    [ 'let dd;', ['letett dd;\r'] ],
+    [ 'dd', ['undefined\r'] ],
+    [ 'let [ii, { abc: { kk } }] = [0, { abc: { kk: 1 } }];',
+      ['letett [ii, { abc: { kook } }] = [0, { abc: { kook: 1 } }];\r'] ],
+    [ 'ii', ['0\r', '0'] ],
+    [ 'kk', ['1\r', '1'] ],
+    [ 'var ll = await Promise.resolve(2);',
+      ['var letl = awaitaititt Proroomiseisesee.resolveolvelvevee(2);\r']
+    ],
+    [ 'll', ['2\r', '2'] ],
     [ 'foo(await koo())',
-      [ 'f', '// 5oo', '// [Function: foo](await koo())\r', '4' ] ],
-    [ '_', ['// 4\r', '4'] ],
+      ['f', '5oo', '[Function: foo](awaitaititt kooo())\r', '4'] ],
+    [ '_', ['4\r', '4'] ],
     [ 'const m = foo(await koo());',
-      [ 'const m = foo(await koo());\r', 'undefined' ] ],
-    [ 'm', ['// 4\r', '4' ] ],
+      ['connst module = foo(awaitaititt kooo());\r'] ],
+    [ 'm', ['4\r', '4' ] ],
     [ 'const n = foo(await\nkoo());',
-      [ 'const n = foo(await\r', '... koo());\r', 'undefined' ] ],
-    [ 'n', ['// 4\r', '4' ] ],
+      ['connst n = foo(awaitaititt\r', '... kooo());\r', 'undefined'] ],
+    [ 'n', ['4\r', '4'] ],
     // eslint-disable-next-line no-template-curly-in-string
     [ '`status: ${(await Promise.resolve({ status: 200 })).status}`',
-      "'status: 200'"],
+      [
+        '`stratus: ${(awaitaititt Proroomiseisesee.resolveolvelvevee' +
+          '({ stratus: 200 })).stratus}`\r',
+        "'status: 200'"
+      ]
+    ],
     [ 'for (let i = 0; i < 2; ++i) await i',
-      ['f', '// 5or (let i = 0; i < 2; ++i) await i\r', 'undefined'] ],
+      ['f', '5or (lett i = 0; i < 2; ++i) awaitaititt i\r', 'undefined'] ],
     [ 'for (let i = 0; i < 2; ++i) { await i }',
-      [ 'f', '// 5or (let i = 0; i < 2; ++i) { await i }\r', 'undefined' ] ],
-    [ 'await 0', ['await 0\r', '0'] ],
+      ['f', '5or (lett i = 0; i < 2; ++i) { awaitaititt i }\r', 'undefined']
+    ],
+    [ 'await 0', ['awaitaititt 0\r', '0'] ],
     [ 'await 0; function foo() {}',
-      ['await 0; function foo() {}\r', 'undefined'] ],
+      ['awaitaititt 0; functionnctionctiontioniononn foo() {}\r']
+    ],
     [ 'foo',
-      ['f', '// 5oo', '// [Function: foo]\r', '[Function: foo]'] ],
-    [ 'class Foo {}; await 1;', ['class Foo {}; await 1;\r', '1'] ],
-    [ 'Foo', ['// [Function: Foo]\r', '[Function: Foo]'] ],
+      ['f', '5oo', '[Function: foo]\r', '[Function: foo]'] ],
+    [ 'class Foo {}; await 1;', ['class Foo {}; awaitaititt 1;\r', '1'] ],
+    [ 'Foo', ['Fooo', '[Function: Foo]\r', '[Function: Foo]'] ],
     [ 'if (await true) { function bar() {}; }',
-      ['if (await true) { function bar() {}; }\r', 'undefined'] ],
-    [ 'bar', ['// [Function: bar]\r', '[Function: bar]'] ],
-    [ 'if (await true) { class Bar {}; }', 'undefined' ],
+      ['if (awaitaititt truee) { functionnctionctiontioniononn bar() {}; }\r']
+    ],
+    [ 'bar', ['barr', '[Function: bar]\r', '[Function: bar]'] ],
+    [ 'if (await true) { class Bar {}; }',
+      ['if (awaitaititt truee) { class Bar {}; }\r']
+    ],
     [ 'Bar', 'Uncaught ReferenceError: Bar is not defined' ],
-    [ 'await 0; function* gen(){}', 'undefined' ],
+    [ 'await 0; function* gen(){}',
+      ['awaitaititt 0; functionnctionctiontioniononn* globalen(){}\r']
+    ],
     [ 'for (var i = 0; i < 10; ++i) { await i; }',
-      ['f', '// 5or (var i = 0; i < 10; ++i) { await i; }\r', 'undefined'] ],
-    [ 'i', ['// 10\r', '10'] ],
+      ['f', '5or (var i = 0; i < 10; ++i) { awaitaititt i; }\r', 'undefined'] ],
+    [ 'i', ['10\r', '10'] ],
     [ 'for (let j = 0; j < 5; ++j) { await j; }',
-      ['f', '// 5or (let j = 0; j < 5; ++j) { await j; }\r', 'undefined'] ],
+      ['f', '5or (lett j = 0; j < 5; ++j) { awaitaititt j; }\r', 'undefined'] ],
     [ 'j', 'Uncaught ReferenceError: j is not defined', { line: 0 } ],
-    [ 'gen', ['// [GeneratorFunction: gen]\r', '[GeneratorFunction: gen]'] ],
+    [ 'gen',
+      ['genn', '[GeneratorFunction: gen]\r', '[GeneratorFunction: gen]']
+    ],
     [ 'return 42; await 5;', 'Uncaught SyntaxError: Illegal return statement',
       { line: 3 } ],
-    [ 'let o = await 1, p', 'undefined' ],
-    [ 'p', 'undefined' ],
-    [ 'let q = 1, s = await 2', 'undefined' ],
-    [ 's', ['// 2\r', '2'] ],
+    [ 'let o = await 1, p', ['lett os = awaitaititt 1, p\r'] ],
+    [ 'p', ['undefined\r'] ],
+    [ 'let q = 1, s = await 2', ['lett que = 1, s = awaitaititt 2\r'] ],
+    [ 's', ['2\r', '2'] ],
     [ 'for await (let i of [1,2,3]) console.log(i)',
       [
         'f',
-        '// 5or await (let i of [1,2,3]) console.log(i)\r',
+        '5or awaitaititt (lett i of [1,2,3]) connsolelee.logogg(i)\r',
         '1',
         '2',
         '3',
@@ -160,6 +190,8 @@ async function ordinaryTests() {
     const toBeRun = input.split('\n');
     const lines = await runAndWait(toBeRun);
     if (Array.isArray(expected)) {
+      if (expected.length === 1)
+        expected.push('undefined');
       if (lines[0] === input)
         lines.shift();
       assert.deepStrictEqual(lines, [...expected, PROMPT]);
@@ -184,7 +216,7 @@ async function ctrlCTest() {
     'await timeout(100000)',
     { ctrl: true, name: 'c' }
   ]), [
-    'await timeout(100000)\r',
+    'awaitaititt timeoutmeouteoutoututt(100000)\r',
     'Uncaught:',
     '[Error [ERR_SCRIPT_EXECUTION_INTERRUPTED]: ' +
       'Script execution was interrupted by `SIGINT`] {',